Leader of the Christian Democratic Union (CDU) and the acting German Chancellor Angela Merkel and Social Democratic Party (SPD) leader Martin Schulz shakes hands before exploratory talks about forming a new coalition government at the SPD headquarters in Berlin, Germany, January 7, 2018. REUTERS/Hannibal Hanschke

Negotiators for her conservative bloc and the centre-left Social Democrats (SPD) told Reuters the parties had agreed in exploratory talks on forming a government that the targeted cut in emissions could no longer be achieved by 2020.

Instead, they would aim to hit the 40 percent target in the early 2020s, the sources said, adding that both parties are still sticking to their goal of achieving a 55 percent cut in emissions by 2030.

The deal would represent something of a u-turn by Merkel, who has long presented herself as an advocate for climate protection policies on the international stage.